Shear wave elastography in the evaluation of liver fibrosis in children

Shear-wave elastography (SWE) is a novel noninvasive method that involves application of local mechanical compression on soft tissue using focused ultrasonography and acquiring strain images that show tissue response. In this study, our goal was to assess the performance of SWE in the staging of liver fibrosis in children with chronic liver disease.

The study involved measuring SWE values in the right lobe of the liver in a patient group of 76 children with chronic liver disease and a control group of 50 healthy subjects. In the patient group, the shear elastic modulus values were correlated with biopsy results according to the Brunt scoring system (F0: portal fibrosis, F1: perisinusoidal or portal/periportal fibrosis, F2: both perisinusoidal and portal/periportal fibrosis, F3: bridging fibrosis, and F4: cirrhosis). Performance of SWE in estimating liver fibrosis in children was determined based on a receiver-operating characteristics (ROC) analysis.

Mean SWE values of the control group and F0 group were not statistically significantly different (P = 0.106). The mean SWE values of the F1, F2, F3, and F4 groups were higher than that of the control group (all P < 0.001). Based on kiloPascal measurement values, the area under the ROC curve was 95.2% (95% confidence interval [CI] 92.1-99.5), with a sensitivity for diagnosing liver fibrosis of 91.5%, a specificity of 94.0%, a positive predictive value of 93.1%, and a negative predictive value of 92.6%. Based on meter-per-second measurement values, the area under the ROC curve was 96.3% (95% CI 92.7-99.8), with a sensitivity for diagnosing liver fibrosis of 93.2%, a specificity of 94.0%, a positive predictive value of 93.2%, and a negative predictive value of 94.0%. Mean SWE values for patients with nonalcoholic steatohepatitis were higher than those in the remainder of the study group.

Although liver fibrosis can be detected using SWE, differentiation of fibrosis stages could not be achieved. The presence of steatosis significantly increased the mean SWE values on elastography and so care should be taken when assessing children with nonalcoholic steatohepatitis.